Re: git-describe --contains

On Aug 11 2017, Davide Cavallari [off-list ref] wrote:

Please help me understand how this command works. There is one case in the
linux kernel repository that puzzles me. Let's consider patch "drm/i915/
execlists: Reset RING registers upon resume" [1]. This patch was committed 641
commits after version 4.8-rc2:

~$ git describe bafb2f7d4755bf1571bd5e9a03b97f3fc4fe69ae
v4.8-rc2-641-gbafb2f7d4755

So I would expect to find it in version 4.8-rc3 and later versions.

However, if I search for the tag that follows (and hence contains) that
commit, I do not find version 4.8-rc3, nor version 4.8, nor version 4.9, but
4.10-rc1:

~$ git describe --contains bafb2f7d4755bf1571bd5e9a03b97f3fc4fe69ae
v4.10-rc1~154^2~44^2~178

Why? Why not v4.8-rc3? This means that the patch has been included neither in
v4.8 nor in v4.9, but only in version 4.10-rc1, right? Why so much time was
needed, considering it was the 621st commit on top ov v4.8-rc2?

You have to ask that the maintainers of the drm subsystem.  If you look
at commit 5481e27f6fd06b7cb902072e81d6b083db8155eb you see that the
branch containing the above commit was merged into a branch that follows
v4.9-rc2, which eventually was merged into v4.10-rc1.

BTW, what are the numbers 154^2~44^2~178 that follow the tag name?

See git-rev-parse(1).  '~N' means to go back N parents, ^N means to pick
parent N of a merge commit.

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
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